The Longitudinal Aging Study in India (LASI) is a multidisciplinary, internationally harmonized panel study designed to be nationally representative of India's population aged 45 and older. LASI collects information conceptually comparable to that gathered by the Health and Retirement Study (HRS) and its sister surveys in Asia, Europe, and elsewhere. LASI has brought innovations related to social connectedness, expectations, informal labor market activity, and pension participation. LASI also collects physical measures of health, including dried blood spot (DBS) specimens. Fieldwork for a four-state pilot study funded by the National Institute on Aging (1R21AG032572-01) was successfully implemented in late 2010. Building on the success of the LASI pilot survey, we will implement the first two waves of a large-scale, nationally representative panel survey on aging, health, and retirement in India, with sufficient statistical power to test hypotheses and make meaningful inferences at the national and (large) state level, and in key subpopulations. LASI will allow a better understanding of the determinants and consequences of India's population aging processes and will inform the design of appropriate evidence-based policies to address key challenges associated with population aging. Our public, internationally harmonized data will also allow for cross-national comparative studies on aging. We will field the full-scale, national LASI survey in 15 states, which together make up more than 90% of India's population. The survey instrument will be based on the pilot survey instrument, which was carefully designed to collect information compatible with other HRS-type surveys, while fully capturing key contextual characteristics of India. The target sample for LASI is non- institutionalized Indian residents aged 45 and older and their spouses (irrespective of age). We will draw 18,000 age-qualifying individuals from a stratified, multi-stage, area probability sampling design. Efforts are well unde way to raise additional, non-NIA/NIH funding to extend LASI coverage to India's smaller states and increase sample size and to thereby allow for a more extensive set of state-level inferences and cross-state comparisons. Wave 1 of LASI survey data will be collected in 2013-2014 through face-to-face interviews using Computer Assisted Personal Interviewing. We will then develop and test a longitudinal survey instrument and methods that will be appropriate for follow-up waves, using the pilot sample. Based on the knowledge gained from Wave 1 and the longitudinal methods study using the pilot sample, we will implement Wave 2 in 2015- 2016. In the course of implementing Wave 2, we will seek to follow best practices from the Indonesia Family Life Study, which achieved a 6% attrition rate. Descriptive and analytic studies of the data will be performed, providing insights for scientific researchers and policy makers in India and beyond. De-identified and cleaned data will be made publicly available within one year of fieldwork completion, enabling scientists both within and outside India to use the rich LASI data. Through comparative studies, LASI will enrich scientific insights and policy development in countries besides India. In particular, LASI will provide new research opportunities in the United States and in countries that host comparable HRS-type surveys, such as China and Indonesia.